A construction machine such as a wheel loader is widely used in an operation of conveying and loading earth and sand. In more detail, the wheel loader raises a boom at a position close to a conveying means such as a truck and dumps a bucket containing earth and sand to load the earth and sand on the conveying means. Then, after the bucket is crowded to a horizontal position, a boom is lowered to fill earth and sand in the bucket. Such an operation is repeated a plurality of times until earth and sand is filled in the conveying means. Thus, a wheel loader operator needs to repeatedly perform an operation of raising and lowering the bucket from and to the conveying means.
In recent years, a position control system for, if a bucket lever and a boom lever are operated, maintaining the bucket lever and the boom lever at a manipulated state with an electromagnet, and if the bucket and the boom reach a predetermined position, returning the bucket lever and the boom lever to an original position to automatically move the bucket and the boom to a specific position so that the repeated operation can be easily performed is used.
However, the above-mentioned position control system needs to manipulate the bucket lever first so that the bucket reaches a specific position, and then manipulate the boom lever to move the boom to a specific position. That is, since the position control system needs to individually manipulate the bucket lever and the boom lever, manipulation efficiency is lowered. In addition, since the boom needs to be moved to a specific position only after the bucket is moved to the specific position thereof, an operation cannot be promptly performed.
Moreover, since an electromagnetic system needs to be used to maintain the bucket lever and the boom lever in a manipulated state, manufacturing costs of the construction machine are increased.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.